Vehicles may employ an on-board electrical energy storage system that may provide electric power that may be used by an electric motor/generator for vehicle propulsion and other purposes. An electric charging system may be employed to electrically charge an on-board electrical energy storage system. An off-board charging module may connect to an on-board electric power distribution system that is part of an electric charging system. Electric power flow to effect charging may be limited due to design constraints of the on-board electric power distribution system and the electric charging system. Charging time to achieve a maximum state-of-charge of an on-board electrical energy storage system is determined based upon magnitude of electric power flow.